Abstract

Probiotics and Gut Microbiome - A Prophylactic and Therapeutic landscape

Neerja Hajela, Head , Yakult Danone India Private Ltd

For centuries, clinicians have described the uterus as a sterile microbe free environment. Today we know that view is totally outdated and the placenta and amniotic fluid is full of microbes1. Early studies evaluating microbiomes in lean and obese mice indicate changes in the relative abundances of the two main phyla, Bacteroidetes and Firmicutes were associated with obesity 2,3. The vaginal microbiota appears to play a significant role in preventing bacterial vaginosis, yeast infections, sexually transmitted infections, urinary tract infections, and HIV infection4. The recent finding that the lower respiratory tract is not sterile and there exists a core lung microbiome all point to the importance of microbes in human health.

 The largest consortium of these microbes is found in the gut and our understanding of their role in human nutrition comes from breakthroughs in molecular profiling of the phylogeny and metabolic capacities of the microbiota5. The gut microbiota produces a variety of nutrients including short chain fatty acids, Vitamin K and constituents of Vitamin B that are utilized by the host6,7 .The fermentation of unabsorbed carbohydrates to organic acids like lactate and short chain fatty acids is provided by a consortium of microbes that are present in the gut.

Diet is the primary driver of the changes in microbial community and current knowledge suggests that manipulation of the gut microbiota with probiotics may be a promising approach for modulating the gut microbiome and the metabolism of short chain fatty acids, amino acids, bile acids and plasma lipoproteins.

Scientific and clinical evidence having progressed rapidly for the possible utility of probiotics and there is both academic and clinical excitement in their benefit for improvement of health and prevention of disease11. Decades of research have identified some promising gastrointestinal and immune targets for probiotics that include maintenance of a healthy intestinal function, improved tolerance to antibiotics and an overall reduced risk for different chronic diseases. Moreintriguing targets of probiotic usage are metabolic disorders like diabetes and obesity where studies in animal models indicate functional involvement of the microbiota. Other clinical application of probiotics indicate that some probiotic strains could diminish the incidence of postoperative inflammation in cancer patients and reduce the risk of cancer especially bladder, breast and colorectal cancers12,13,14. Researchers are beginning to open the book on the gut brain axis and recent advances indicate that the gut microbiota could influence brain development and behaviour of the host through a bidirectional communication system that integrates neural, hormonal and immunological signalling between the gut and the brain 15. This extended communication system may be modulated by a class of probiotics called psychobiotics to treat a broad spectrum of complex central nervous system diseases.

Probiotics have come a long way in 100 years since Metchnikoff and 10 years since their globalization and the next decade promises their application in more ways than can be visualized today.